Modern orthodontic techniques include repositioning teeth that are misaligned, too close together or otherwise mis-positioned. In order to reposition the teeth, the teeth are connected to an arch wire that serves as a guide, urging the teeth into the desired position and orientation. In order to connect the teeth to the arch wire, small brackets with slots for receiving the arch wire are attached to the teeth. The ends of the arch wire are normally attached to the molars with another orthodontic appliance known as a buccal tube. In some cases, the bracket or tube is brazed or welded or brazed to a metal band placed around the patient's tooth. However, the preferred method of attaching brackets to a patient's teeth is by means of an adhesive. Bonding brackets to a patient's teeth is more comfortable for the patient, cosmetically more appealing and faster in practice than the use of metal bands.
Applying an appropriate amount of adhesive to the base of an orthodontic appliance such as a bracket or buccal tube can be a time consuming and tedious task for the orthodontist or his or her assistant. Too little adhesive may result in the bracket coming loose from the tooth after installation while an excessive amount of adhesive will be pushed out from between the bracket and tooth, requiring removal. Further, while two-part chemically curing adhesive systems are available for bonding orthodontic brackets to a patient's teeth, many practitioners prefer photo sensitive adhesives that are cured upon exposure to light in the visible spectrum for a relatively short period. Consequently, time is also a factor insofar as the adhesive applied to the bracket can only be exposed to visible light for a limited period before the bracket is positioned on the tooth.
In order to address these issues, pre-pasted orthodontic appliances were developed. Pre-pasted orthodontic appliances have an adhesive, normally a photo sensitive, light curing adhesive, applied to the base of the bracket before the bracket is packaged. Pre-pasted brackets reduce the amount of time required to install brackets on the patient's teeth by eliminating the need for the orthodontist to apply the adhesive to the bracket. Pre-pasted brackets also reduce the amount of wasted adhesive as the manufacturer can precisely control the amount and placement of the adhesive on the base of the bracket.
Packaging for brackets with a pre-applied light curing adhesive must protect the adhesive from exposure to light, as well as from contamination and evaporation. Further, if the adhesive adheres to the package, the adhesive coating may be disturbed when the bracket is removed from the package. Thus, in some cases, the pre-pasted portion of the orthodontic appliance is isolated from the package material with a release coating or layer. In addition, the package should present the bracket to the orthodontist in a fashion that facilitates quick and convenient removal of the bracket from the package.